Fan control system

ABSTRACT

The present invention relates to a fan control system. The fan control system includes a first micro controller, a second micro controller and a first logic circuit. The first micro controller provides at least one first control signal. The second micro controller is connected to the first micro controller. The second micro controller detects operational status of the first micro controller, and provides at least one second control signal. The first logic circuit receives the first control signal and the second control signal to process logic operation and to generate at least one driving signal to fan. The fan control system of the invention utilizes two micro controllers, when one of the two micro controllers malfunctions, the first logic circuit allows the other micro controller to continue proper operation of the fan, thereby preventing the problem of insufficient heat dissipation that results from malfunction of the single micro controller of a conventional fan control system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a control system, and more particularly, to a fan control system.

2. Description of the Related Art

FIG. 1 shows a schematic block diagram of a conventional fan control system. The conventional control system 10 includes a micro controller 11 for providing pulse width modulation (PWM) signals to a fan assembly 12. The fan assembly 12 includes a plurality of fans for dissipating heat. Because the conventional control system 10 has only a micro controller 11, when the micro controller 11 malfunctions and cannot provide PWM signals to the fan assembly 12, the fans in the fan assembly 12 cannot work to dissipate heat from the whole system, causing the whole system to become unstable and fail to work properly.

Therefore, it is necessary to provide a fan control system to solve the above problem.

SUMMARY OF THE INVENTION

The present invention provides a fan control system, comprising: a first micro controller, a second micro controller and a first logic circuit. The first micro controller provides at least one first control signal. The second micro controller is connected to the first micro controller. The second micro controller detects the operational status of the first micro controller, and provides at least one second control signal. The first logic circuit receives the first control signal and the second control signal to process logical operations and to generate at least one driving signal to at least one fan.

The fan control system of the invention utilizes two micro controllers. When one of the two micro controllers malfunctions, the first logic circuit allows the other micro controller to continue proper operation of the fan, thereby preventing the problem of insufficient heat dissipation that results from malfunction of the single micro controller of a conventional fan control system. Furthermore, each of the two micro controllers can detect the operational status of the other so that when one of the two micro controllers malfunctions, an alarm is actuated to alert users to the need for repair.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a conventional fan control system; and

FIG. 2 is a schematic block diagram of the fan control system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 is a schematic block diagram of the fan control system according to the present invention. The fan control system 20 of the invention comprises: a first micro controller 21, a second micro controller 22 and a first logic circuit 23. The first micro controller 21 provides at least one first control signal to the first logic circuit 23. In this embodiment, the first control signal serves as a first pulse width modulation signal.

The second micro controller 22 is connected to the first micro controller 21. The second micro controller 22 detects the operational status of the first micro controller 21, and provides at least one second control signal to the first logic circuit 23. The first logic circuit 23 receives the first and second control signals to process logic operations and to generate at least one driving signal to at least one fan. In this embodiment, the fan is a fan assembly 30 comprising twelve fans.

In this embodiment, the first logic circuit 23 is a logic OR circuit to process a logical OR operation on the first and second control signals. The first control signal serves as the first pulse width modulation signal. When the second micro controller 22 detects the first micro controller 21 under normal operating conditions, and the second control signal serves as a low logic level signal (L). After the logical OR operation of the first logic circuit 23, the driving signal serves as the first pulse width modulation signal.

When the second micro controller 22 detects the first micro controller 21 under abnormal operating conditions, the second control signal serves as a high logic level signal (H). After the logical OR operation of the first logic circuit 23, the driving signal serves as the high logic level signal (H). That is, when the first micro controller 21 malfunctions, the first control signal is unknown. Thus, the second control signal is set to serve as the high logic level signal (H) so that the fans continue to operate in full speed, thus avoiding the problem of insufficient heat dissipation that would otherwise result from fan failure.

In another embodiment, the first control signal serves as a first pulse width modulation signal. When the second micro controller 22 detects the first micro controller 21 under normal operating conditions, the second control signal serves as a low logic level signal (L) so that the driving signal serves as the first pulse width modulation signal. When the second micro controller 22 detects the first micro controller 21 under abnormal operating conditions, the second control signal serves as a second pulse width modulation signal so that the driving signal serves as the second pulse width modulation signal.

That is, when the first micro controller 21 malfunctions, if the first micro controller 21 cannot work, and cannot provide the first control signal. Thus, the second micro controller 22 replaces the first micro controller 21 to take the control power, and the second control signal serves as the second pulse width modulation signal to make the fans work normally, thus avoiding the problem of insufficient heat dissipation that would otherwise result from fan failure.

The fan control system 20 of the invention further comprises a rotating speed detector 26 for detecting the rotating speed of the fan assembly 30 and for generating at least one rotating speed signal to the second micro controller 22. The second micro controller 22 transmits the rotating speed signal to the first micro controller 21. According to the rotating speed signal, the first micro controller 21 can adjust the first control signal, or the second micro controller 22 can adjust the second control signal so as to control the rotating speed of the fan assembly 30 to be a predetermined speed.

The fan control system 20 of the invention further comprises a second logic circuit 24 and an alarm 25, wherein the first micro controller 21 further provides at least one first alarm signal to the second logic circuit 24, the second micro controller 22 further provides at least one second alarm signal to the second logic circuit 24. The second logic circuit 24 receives the first alarm signal and the second alarm signal to process logic operation and to generate at least one actuating signal to the alarm 25.

In this embodiment, the second logic circuit 24 is a logic OR circuit. When one of the first micro controller 21 or the second micro controller 22 malfunctions, the second logic circuit 24 processes logical OR operation on the first alarm signal and the second alarm signal to generate the actuating signal to actuate the alarm 25. In this embodiment, the alarm can be a warning light or warning buzzer.

The first micro controller 21 further comprises a first communicating interface 211, and the second micro controller 22 further comprises a second communicating interface 221, the first communicating interface 211 and the second communicating interface 221 connects to detect the operational status of the other. When the first micro controller 21 detects the second micro controller 22 under abnormal operating conditions, the first micro controller 21 provides the first alarm signal to actuate the alarm 25. When the second micro controller 22 detects the first micro controller 21 under abnormal operating conditions, the second micro controller 22 provides the second alarm signal to actuate the alarm 25.

Therefore, the fan control system of the invention utilizes two micro controllers. When one of the two micro controllers malfunctions, the first logic circuit allows the other micro controller to continue proper operation of the fan, thereby preventing the problem of insufficient heat dissipation that results from malfunction of the single micro controller of a conventional fan control system. Furthermore, each of the two micro controllers can detect the operational status of the other so that when one of the two micro controllers malfunctions, an alarm is actuated to alert users to the need for repair.

While the embodiment of the present invention have been illustrated and described, various modifications and improvements can be made by those skilled in the art. The embodiments of the present invention are therefore described in an illustrative but not restrictive sense. It is intended that the present invention may not be limited to the particular forms as illustrated, and that all modifications that maintain the spirit and scope of the present invention are within the scope as defined in the appended claims. 

1. A fan control system, comprising: a first micro controller, for providing at least one first control signal; a second micro controller, for connecting the first micro controller and for detecting operational status of the first micro controller, the second micro controller for providing at least one second control signal; and a first logic circuit, for receiving the first control signal and the second control signal to process logic operation and to generate at least one driving signal to at least one fan.
 2. The fan control system according to claim 1, wherein the first logic circuit is a logic OR circuit.
 3. The fan control system according to claim 2, wherein the first control signal is a first pulse width modulation signal, when the second micro controller detects the first micro controller under normal operating conditions, the second control signal serves as a low logic level signal so that the driving signal serves as the first pulse width modulation signal; when the second micro controller detects the first micro controller under abnormal operating conditions, the second control signal serves as a high logic level signal so that the driving signal serves as the high logic level signal.
 4. The fan control system according to claim 2, wherein the first control signal is a first pulse width modulation signal, when the second micro controller detects the first micro controller under normal operating conditions, the second control signal serves as a low logic level signal so that the driving signal serves as the first pulse width modulation signal; when the second micro controller detects the first micro controller under abnormal operating conditions, the second control signal serves as a second pulse width modulation signal so that the driving signal serves as the second pulse width modulation signal.
 5. The fan control system according to claim 1, further comprising a rotating speed detector for detecting the rotating speed of the fan and for generating at least one rotating speed signal to the second micro controller, the second micro controller transmits the rotating speed signal to the first micro controller.
 6. The fan control system according to claim 1, further comprising a second logic circuit and an alarm, wherein the first micro controller is used for further providing at least one first alarm signal to the second logic circuit, the second micro controller is used for further providing at least one second alarm signal to the second logic circuit, the second logic circuit receives the first alarm signal and the second alarm signal to process logic operation and to generate at least one actuating signal to the alarm.
 7. The fan control system according to claim 6, wherein the second logic circuit is a logic OR circuit, when one of the first micro controller or the second micro controller is under abnormal operating conditions, the second logic circuit processes logical OR operation on the first alarm signal and the second alarm signal to generate the actuating signal to actuate the alarm.
 8. The fan control system according to claim 7, wherein the first micro controller further comprises a first communicating interface, and the second micro controller further comprises a second communicating interface, the first communicating interface and the second communicating interface connects to detect the operational status of the first micro controller and the second micro controller. 